I have a new out-of-the-box 16GB USB flash drive and I am unable to erase it in macOS. I've tried via Terminal command, Disk Utility nothing works.


This is what I get when I insert my USB drive


This is how it looks in my Disk Utility


I am out of options after 2 days of researching and getting no luck! Any idea how to fix this?

  • Please add the relevant lines from Terminal command diskutil list.
    – Gilby
    Commented Feb 26, 2022 at 2:53
  • @Gilby you mean command i used? diskutil erasedisk ExFat myUsb disk2
    – mafortis
    Commented Feb 26, 2022 at 2:59
  • 1
    Some older USB keys have a physical write-lock switch. Perhaps this has one? Also, some USB keys just fail to format at all because they got zapped somehow. Chuck this one in the trash and move on. :-)
    – IconDaemon
    Commented Feb 26, 2022 at 3:01
  • @IconDaemon I open the box of this usb last night (brand new) it works just fine on PC but on Mac....
    – mafortis
    Commented Feb 26, 2022 at 3:03
  • I meant diskutil list so we can see the partitions which are on the disk and their format along with the partition table type.
    – Gilby
    Commented Feb 26, 2022 at 6:04

2 Answers 2


First list the disks:

diskutil list

Then try:

diskutil eraseDisk JHFS+ UntitledUFS /dev/disk*

I had the exact same problem. I couldn't use Disk Utility like I've been used to. Instead I ran "diskutil list" I ID'd the USB drive as disk4 and then ran this and it worked:

diskutil eraseDisk exFAT MYUSB /dev/disk4

I'm now happily copying a 33GB wedding video onto the Sandisk 64 GB flash drive.

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